Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to tune away in wireless communication devices such as devices using one or more subscriber identity module (SIM) cards.
A wireless communication device, such as a mobile phone device or a smart phone, may include at least one Subscriber Identity Module (SIM). Each SIM may enable one or more subscriptions. Each subscription may correspond to one or more Radio Access Technologies (RATs). Specifically, with respect to multi-SIM wireless communication devices, when all SIMs are active, the wireless communication device may be a Multi-SIM-Multi-Active (MSMA) device. On the other hand, when one SIM is active while the rest of the SIM(s) is/are standing by, the wireless communication device may be a Multi-SIM-Multi-Standby (MSMS) device. With Dual Sim, Dual Standby (DSDS) or Multi-SIM-Multi-Standby (MSMS) devices only one SIM is active because there is one radio frequency (RF) chain which is shared by the SIMs. The RATs may include, but are not limited to, Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA) (particularly, Evolution-Data Optimized (EVDO)), Universal Mobile Telecommunications Systems (UMTS) (particularly, Wideband Code Division Multiple Access (WCDMA), Long Term Evolution (LTE), Single Radio LTE (SRLTE), Simultaneous GSM and LTE (SGLTE), High-Speed Downlink Packet Access (HSDPA), and the like), Code Division Multiple Access 1× Radio Transmission Technology (1×), General Packet Radio Service (GPRS), Wi-Fi, Personal Communications Service (PCS), and other protocols that may be used in a wireless communications network or a data communications network.
Some wireless devices are configured to facilitate communication on two separate networks via two separate subscriptions. For instance, dual-subscriber identity module (SIM), dual standby (DSDS) devices may include two SIM cards—one card for a first subscription and a second card for a second subscription. Furthermore, each subscription may be associated with one or more technology types. For example, a first subscription may exclusively support 2G communication technology, such as Global System for Mobile Communications (GSM), while the second subscription may support one or more 3G communication technologies (e.g., Wideband Code Division Multiple Access (WCDMA)) and 2G communication technology.
In DSDS devices, a user may establish a call, such as a voice call, data call, data session, text messaging session, or any other data transfer session, via one of the two subscriptions. Because most DSDS devices contain a single radio resource, such as a transceiver, where a first subscription has established an ongoing call with a first subscription network, the UE tunes the transceiver away to the second subscription to receive paging signals and to transmit, for example, message acknowledgement signals and/or measurement indication signals. Therefore, while the first subscription continues an ongoing call, the transceiver may periodically tune away from the first subscription to the second subscription to receive such paging and/or control information.
Therefore, in DSDS devices, a user may engage in a data call via a first subscription, but may intermittently halt the data session to tune away to receive control data associated with the second subscription, which is typically in idle mode. This tune away may lead to reduction in data throughput on the first subscription for its ongoing data call, as no data transfer takes place relative to the data call while the device tunes away to the second subscription which is then using radio resources such as the transceiver. What is more, the second subscription may hold the radio resources for a long period of time in order to complete software processing related to base station registration, which exacerbates the reduced data throughput problem on the first subscription. Tune away cannot be avoided completely, however, as the second subscription periodically receives control data from its network, such as paging messages and the like.
A DSDS device may also support carrier aggregation (CA), which is simultaneous operation on multiple carriers. Multi-mode transceivers including Long Term Evolution (LTE)/Frequency Division Duplex (FDD), LTE/Time Division Duplex (TDD), Circuit-Switched FallBack (CSFB), Simultaneous Voice and LTE (SVLTE), Simultaneous GSM and LTE (SGLTE), Dual SIM Dual Standby (DSDS), and other similarly-configured devices can co-exist in several different combinations.
Thus, methods and apparatuses are used to allow for increased performance on the first technology as it continues an active data session while allowing the second subscription to tune away to receive messages.